SUMMARY During pregnancy, maternal metabolism changes to support the gravid uterus and the timing of these changes are a function of both gestational length and fetal number. In order to predict the nutrient requirements throughout pregnancy, it is necessary to know the changes which occur in both the reproductive and maternal tissues. Fifty-seven (57) wild grasscutters were used to investigate the increased nutrient requirement of fetal growth on reproductive and maternal tissues in the grasscutter. The animals were categorized into non-pregnant, early pregnancy (d 1 -50), mid pregnancy (d 51 -100), and late pregnancy (> d 100) status. Maternal organ weights were reported as fresh weight (g), scaled to empty body weight (EBW; g/g), and maternal body weight (MBW; g/g). Carcass weight declined with advancing pregnancy (P = 0.029), as were the lungs, small and large intestines whilst the weights of the kidneys, liver and remaining viscera increased. The total internal organ mass, due mainly to the significant increases in the 'remaining viscera' mass, which is made up of mainly adipose tissues, also increased with advancing pregnancy. From mid pregnancy to late pregnancy, uterine weight increased by 675. 3% (52.33±6.525 v. 353.37±26.580). This suggests that pregnancy imposes a huge metabolic demand on the grasscutter, but the animals appear to mobilize maternal nutrient stores, as well as slow down metabolic rate (as indicated by the increases in the fat component of the remaining viscera mass) to meet requirements of the growing fetus and developing mammary glands
